I see you are trying to make the AI a bit more difficult or challenging by making their army sizes bigger. This wont really help because it will just take longer to kill them than making it harder.
One suggestion that I can give is by making their reinforcement troop type better.
Open the M&B Warband Mod Tool, go to Party Template editor and you will see there is pt_kingdom_1_Reinforcements_a, pt_kingdom_1_Reinforcements_b and pt_kingdom_1_Reinforcements_c
Someone explained this on a different post http://forums.taleworlds.com/index.php/topic,46290.msg1270446.html#msg1270446 (at the bottom)
pt_kingdom_1_Reinforcements_a reinforces 65% and pt_kingdom_1_Reinforcements_b reinforces 35% to Cities and Castles.
pt_kingdom_1_Reinforcements_a reinforces 50%, pt_kingdom_1_Reinforcements_b reinforces 25% and pt_kingdom_1_Reinforcements_c reinforces 25% to AI Lords.
There you can say what troop each faction's City, Castle and AI lords should get and how many of each troop. This gets a bit tricky because if you put too many troops in pt_kingdom_1_Reinforcements_a then it will get over populated. Good example is I have added 4 extra troops in that list and then the cities had something like 600 troops garrisoned, the AI lords wont get too many because they are limited to skills.
What I thought about is to take out all the low end troops and populate it with stronger troops, this can end up good or bad for the player.
Firstly you early game will be F***ing hard because all the AI lords will have very powerful troops, so you will have to live off bandits for a while and level that Trainer skill. End game will be a lot more fun because the towns will have tough troops in and the AI lords wont be a walkover.
Just remember that the Towns wont get the new reinforcements with an old save game, once they lose some troops it will then spawn the new amounts, if you want to see the changes ASAP then you need to start a new game
There are more information about scripts and other stuff on http://forums.taleworlds.com/index.php/topic,46290.0.html but it is made for M&B and not for Warband, some of the things in there are different now.
I have also tried to change is the amount of income the caravans brings in for the Towns but I only see numbers there and I have no idea how to understand that
I wish I had more time to play around with the pt_kingdom_1_Reinforcements because if you can find a decent balance for the reinforcements the game will really be more fun and challenging.
Now for me its getting a big army and run over every AI lord I can find. It is really boring with ANY mod I am playing now.
The other problem I got is after I have changed some of those reinforcements I got a script error from the Diplomacy mod, when I tried to send out the recruiter from my castle it spammed me with errors but the game still went on and it came from the Party Template txt file so I had to made a new clean copy and start over again
I have actually looked into the troop spawning, for example the Sarranid has only mamluke in pt_kingdom_6_Reinforcements_c, so 25% of the total troops given to the AI lords of the Sarranid is mamluk, each will get 3-6 mamlukes do not know howmany times.
The castles and towns of the Sarranid will only get Footmen, Recruits, Archers and Skirmishers, from there I think the AI lords take troops as they please and put in some other troops etc.
Like I said, this will take a lot of time to make it perfect for the AI and Player. I will keep on playing around with this when ever I get time and share my reports on this matter.
For now I have increased the Mount Troop wages to 250 so that I find it hard to keep up a big cavalry army and focus more on infantry
